Most of our major food crops are annuals, started from seed each year and fully harvested to collect the seeds at the end of their short growing season. By contrast, perennial crops are longer lived, and only partially harvested, so their biomass can increase from year to year. The larger root system of perennials can help with water and nutrient uptake, and help prevent soil erosion. Baker reviews efforts to develop and improve perennial crops, including domestication of wild perennial species and cross-breeding between annuals and perennials, as well as the use of genome mapping, and efforts understanding the interactions between perennials and the soil microbiome. Bioscience 10.1093/biosci/bix018